In environments such as buildings, large ocean-going vessels, and flight craft it is highly desirable to detect smoke at the earliest possible moment, to do so for a large number of spatial sections of the environment in which smoke is to be detected, and to do so without communicating spurious indications of the presence of smoke. The ability to meet these needs is complicated by considerations including cost, technology, and human factors. For example, if a smoke detection system designed for a large building requires a source/detector combination for each of a large number of spatial sections, then the initial cost and projected maintenance costs for the system may render it cost prohibitive, thus forcing resort to cheaper but less effective fire protection schemes. As a further example, the detection of smoke in an environment containing normal airborne particulate matter such as common dust presents the problem of distinguishing between the normal particulates and those accompanying smoke. If the smoke detection system does not consistently make that distinction, then it will occasionally communicate spurious indications of the presence of smoke. Avoiding undesirable electromechanical and/or human-behavioral responses then requires that the system incorporate some form of verification. This necessarily decreases the efficiency of the system and may significantly increase its cost.